// The MIT License - Copyright (c) 2007 Universitetet i Oslo
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE. 
package sg.atom.logic.fuzzy.rules.conditions;

import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.collect.Table;

/**
 * Implementation of a fuzzy literal extractor.
 *
 * @author <a href="romain.rouvoy+funzy@gmail.com">Romain Rouvoy</a>
 * @version $Revision$
 */
public class FuzzyIs<K, V> implements FuzzyCondition<K, V> {

    private K key;
    private V value;

    private FuzzyIs(K variable, V literal) {
        key = variable;
        value = literal;
    }

    public Double evaluate(Table<K, V, Double> provider) {
        Double v = null;
        //FIXME: @atomix change because of type check errors.
//        checkNotNull(provider.get(key), "Variable \'" + key + "\' is invalid").get(value);
        return checkNotNull(v, "Literal \'" + value + "\' is invalid");
    }

    public static final <K, V> FuzzyCondition<K, V> is(K variable, V literal) {
        return new FuzzyIs(variable, literal);
    }
}
